This invention relates to a sewing machine in general, and more particularly to a stop-motion mechanism of a driving pulley for selectively performing stitching operation and thread winding operation.
There has been proposed a stop-motion mechanism of a driving pulley of a sewing machine, for example, in Japanese Utility Model Application No. 100751/1974 (laid open), in which a flywheel is normally connected by a fastening screw to a bushing secured to an upper shaft and is rotated together with the upper shaft, but may be disconnected from the latter by loosening the screw, so that the flywheel may be rotated with respect to the upper shaft. This mechanism is simple in structure but a considerable force is required to manipulate the operating screw.
Additionally, a few attempts have been made to provide a stop-motion mechanism, for example, in Japanese Patent Specifications (published) Nos. 13138/1965 and 5301/1968, wherein an operating member is moved along the upper shaft, thereby separating a flywheel from the upper shaft. Such mechanism is advantageous in that only a small operating force is required, but because of too many components it is difficult and troublesome to assemble and disassemble the same.